When Las Vegas sets a new all-time high temperature record, something unpleasant is happening with the weather. When it is too hot for planes to fly out of Phoenix, or the country sets a new all-time high temperature for June? Be glad that you don't live in the Southwest. Or, if you do, spend a few minutes today giving thanks to the inventor of air conditioning.

Death Valley, as we noted last week, holds the record for the hottest temperature ever recorded on Earth, 134 degrees in 1913. Now it adds another crown: the hottest temperature during June in the continental United States. Congratulations, foolhardy residents of the region, here is your award, it is lots of sweat.

Over the past three days, the temperature at Furnace Creek — site of the 1913 record — averaged 112 degrees. Averaged. At no point during those 72 hours did it drop below 96 degrees. That is ridiculous. (You'll notice that, meanwhile, the humidity barely registered. This was a large part of the problem contributing to the heat wave: no water vapor.)

The National Oceanic and Atmospheric Administration logs daily records across the country. So far, there is only data for Friday and Saturday in the system. But here are all of the broken and tied same-day records during that period. At Iron Mountain, near San Bernadino, a 19-year record for June 28th was beaten by 8.1 degrees.

And of course, Sunday was the hottest day of the weekend. Las Vegas' new all-time record came just before 5 p.m. yesterday when temperatures in the city hit 117 degrees. If you'd ever wondered if Vegas could be more insufferable than it already is, there's your answer. (Just kidding! Vegas is always equally insufferable.)

US Airways had its own problems in Phoenix. Its planes are only certified to 118 degrees, so when the temperature in the city topped that on Saturday, the airline had to cancel flights. The problem is that planes need a certain air density to fly at peak performance, and the hotter the air, the lower the air pressure. If you're curious, which we were: yes, Furnace Creek has an airport.

The first day of a heat wave is kind of fun. It's novel, you get to complain. By day two, it has already gotten tedious. By now, day four or five, civilization has reverted to a microcosm of the city-states that once dominated the Grecian archipelago. Every house for itself; every spoken word understood first as an insult and a challenge to war. If you have friends and family in the Southwest, give them a wide berth for the day (maybe, week). If you are there yourself: May God have mercy on your soul and on your household appliances.

Photo: It seems that heatstroke causes your thumbs to jut out at odd angles and your face to be contorted into a grimace. (Reuters)